Three sons of Hamas political chief Ismail Haniyeh were killed in an Israeli airstrike in Gaza, according to a statement from Hamas.

Three of the brothers’ children were also killed in the strike.

The Israel Defense Forces confirmed the strike and said the sons were part of Hamas' military wing.

During a meeting at the White House on Tuesday with the families of Americans being held hostage by Hamas, Vice President Kamala Harris said there is "no higher priority than reuniting the hostages with their loved ones," according to a White House readout.

Harris also reaffirmed the United States' commitment to bringing home the remains of those hostages who have been confirmed dead, according to the readout.

Rachel Goldberg-Polin, whose 23-year-old son Hersh is being held hostage by Hamas, described the meeting with Harris as "very productive."

“There is a possibility of holding two truths,” Goldberg-Polin told reporters outside the White House. “You can believe, as we do, that it is horrible that innocent civilians in Gaza are suffering, and at the same time you can also know that it is horrible and against international law for hostages to be held against their will."

Goldberg-Polin said her son got his arm blown off during Hamas' attack at the Nova Music festival on Oct. 7. Her husband, Jonathan Polin, said that they "have no choice but to stay hopeful."

Jonathan Dekel-Chen, the father of American hostage Sagui Dekel-Chen, called on Hamas to reach a deal to release the hostages.

"We are waiting now and the world waits for Hamas to get to yes," Dekel-Chen told reporters. "It is in their court."

-ABC News' Juhi Doshi

President Joe Biden called for an immediate cease-fire to get food and aid into Gaza in an interview airing Tuesday night on Univision.

"So I what I'm calling for is for the Israelis to just call for a cease-fire, allow for the next six, eight weeks total access to all food and medicine going into the country," Biden said in the interview with Univision's Enrique Acevedo. "I've spoken with everyone from the Saudis to the Jordanians to the Egyptians. They're prepared to move in. They're prepared to move this food in. And I think there's no excuse to not provide for the medical and the food needs of those people. It should be done now."

Biden did not mention tying the cease-fire to a hostage deal, according to a transcript of the interview, which would be a shift for the administration. ABC News has reached out to the White House for comment.

Last week, officials pushed back on suggestions that they were separating calls for a cease-fire from hostage negotiations in their readout of Biden's call with Israeli Prime Minister Benjamin Netanyahu.

"Our conviction remains that we need to see an immediate cease-fire to enable the release of hostages but also to enable a dramatic surge in humanitarian assistance, as well as obviously better protecting civilians," Secretary of State Antony Blinken said on April 4.

In the Univision interview, Biden also called Netanyahu's approach in Gaza "a mistake" when asked if he believed the prime minister was "more concerned about his political survival than he is in the national interest of his people" as calls for Netanyahu's resignation have increased following the strike that killed seven World Central Kitchen workers.

"Well, I will tell you, I think what he's doing is a mistake. I don't agree with his approach. I think it's outrageous that those four, three vehicles were hit by drones and taken out on a highway where it wasn't like it was along the shore, it wasn't like there was a convoy moving there, etc.," Biden said in the interview.

The hour-long interview, which is airing at 10 p.m. ET, was taped a day before Biden's call with Netanyahu on April 4.

-ABC News' Molly Nagle

President Joe Biden's plan to use the military to build a giant pier off the coast of Gaza to deliver food, water and medicine will cost at least $180 million and could top $200 million, ABC News has learned.

The price tag was described by two people familiar with the initial estimate, which has not been released by U.S. Central Command.

The price tag is expected to fluctuate as U.S. officials scramble to finalize key details on the project, including which humanitarian organizations and foreign governments are willing to help carry the shipments to shore and distribute them.

The floating dock is expected to be nearly the size of a football field -- about 97 feet wide and 270 feet long -- stationed about 3 miles offshore. Container ships would screen their cargo in Cyprus before taking it to the floating dock and unloading it. From there, the aid would be moved aboard small Army ferries that would transport it to an 1,800-foot "trident" pier that connects to shore.

Officials also continue to discuss how to protect the service members who will be 3 miles offshore, where Hamas is believed to still operate.

The project -- which triggered the deployment of six Army and Navy ships and will involve some 1,000 U.S. military troops -- is on track to become operational in early May, enabling the delivery of some 2 million meals per day.

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-ABC News’ Anne Flaherty and Luis Martinez